JP2810082B2 - Axial gas laser with auxiliary electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an axial flow gas laser, and more particularly, to an axial flow gas laser.
The present invention relates to a laser tube provided with an auxiliary electrode.

(Prior Art) FIG. 4 is a schematic view of a conventional axial flow gas laser. As shown, the axial flow gas laser 1 has a laser tube 3 and an output mirror.
5, a rear mirror 7, a gas inlet 9, an outlet 11, an anode 13, a cathode 15, a power source E and the like. Since the temperature of the laser gas in the laser tube 3 becomes high due to the discharge, it goes out of the tube as shown by the arrow, is cooled by a cooling device (not shown), and is circulated. The discharge occurs along the gas flow in the tube, as shown in the hatched area in the figure, offset to the central tube wall. The laser gas is excited by the discharge between the two electrodes, and the dielectrically-emitted light is reciprocated between the output mirror 5 and the rear mirror 7 and amplified, oscillates, and a part thereof is extracted from the output mirror 5 as laser light L.

In FIG. 5, a plurality of laser gas inlets 9 and outlets 11 shown in FIG. 4 are provided at equal intervals on the circumference of the laser tube, and a plurality of anodes 13 are provided at the inlet 9 (n). Provided, cathode 15
Is a ring shape. The plurality of anodes 13 are connected to the power supply E through separate resistors R so that the discharge is uniform for each electrode.
It is connected to the. In the axial-flow type gas laser formed as described above, the flow of the laser gas is more uniform than in the former, and the discharge portion has a shape as shown by oblique lines along the flow.

(Problems to be Solved by the Invention) As described above, in the apparatus described with reference to FIG. 4, since the discharge portion is generated to be offset to the central tube wall, the utilization efficiency of the laser gas is small, and therefore, the apparatus becomes large for the output. Was. In the case of FIG. 5, the volume of the discharge part is larger than that of the former, and the laser output also increases. However, the discharge part contracts from the middle part of the laser tube to the cathode, and the temperature of the laser gas is reduced in the contracted part. , The conversion efficiency of the discharge power into laser light was reduced.

The present invention has been made in view of such a problem, and reduces the contraction of the discharge cross section from the intermediate portion of the laser tube to the cathode as seen in the above-described conventional example, thereby effectively utilizing the laser gas. It is another object of the present invention to provide a laser tube capable of efficiently converting discharge power into laser light.

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above object, an axial flow gas laser provided with an auxiliary electrode according to the present invention is provided at one end of a laser tube at equal intervals along a circumference. A plurality of pin-shaped electrodes are provided, a ring-shaped electrode is provided at the other end, and a plurality of pin-shaped auxiliary electrodes are provided at regular intervals along the circumference in the middle of the laser tube. And two pins connected in series between the pin-shaped electrodes provided at the one end and between the intermediate connection point of the two resistors and the ring-shaped electrode provided at the other end. And a power supply for discharging.

(Operation) Since the ring-shaped electrode is used as the cathode, the potential of the pin-shaped auxiliary electrode disposed in the middle part of the laser tube is the same as the conventional case without the auxiliary electrode. Rise from the potential at this position. Therefore, a discharge is generated between the auxiliary electrode and the ring-shaped cathode, so that the conventional contraction of the discharge portion is reduced. In this case, the main discharge is performed between the plurality of pin-shaped electrodes at one end of the laser tube and the ring-shaped cathode.

(Example) Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of an axial gas laser embodying the present invention. This axial-flow gas laser 1 has a laser tube 3, an output mirror 5, a rear mirror 7, an inlet 9, an outlet 11, a plurality (n) of anodes 13, as in the above-described conventional example (FIG. 5). A ring-shaped cathode 15 and the like are provided as shown in the figure, and further, a plurality of pin-shaped auxiliary electrodes 17 are provided along the circumference at the intermediate portion of the laser tube 3, and these and the plurality of anodes are provided. Series resistance between 13 and
R ₁ and R ₂ are inserted, and a discharge power source E is connected between the connection point 19 of the series resistors R ₁ and R ₂ and the ring-shaped cathode 15.

The reason for providing the resistors R ₁ and R ₂ is to make the potential at the position of the auxiliary electrode appropriately higher than the potential at the same position of the laser tube when this is not provided.

The electrical equivalent circuit of the laser tube 3 is as shown in FIG. Here, Rg ₁ and Rg ₂ are respectively supplied from the anode 13 to the auxiliary electrode 1.
7, The electric resistance of the laser gas from the auxiliary electrode 17 to the cathode 15. Assuming that nR _{1 in} this circuit diagram is equal to nR in FIG. 5 described above, the circuit resistance decreases and the current increases as nR ₂ is inserted. Therefore, the voltage across Rg ₂ increases. That is, the voltage of the auxiliary electrode increases because nR ₂ is inserted.

The voltage distribution in the axial direction of the laser tube 3 during discharge (x-axis in FIG. 3) cannot be expressed by a simple equation due to ionization of the laser gas, but the horizontal axis indicates the positions of the anode 13, the auxiliary electrode 17, and the cathode 15. Are taken as O, l _o and l, respectively, and the voltage V is taken on the vertical axis, as shown in FIG. The solid line indicates the case where the auxiliary electrode of the present invention is provided, and the dotted line indicates the case of the conventional example (FIG. 5). That is, when the auxiliary electrode is provided, the voltage distribution moves upward between the two electrodes, and increases by ΔV at the position of the auxiliary electrode.

[Effects of the Invention] As can be understood from the above description, the present invention is provided with the configuration described in the claims, so that the discharge unit from the intermediate portion to the cathode of the conventional laser tube is provided. Is reduced, and the utilization efficiency of the laser gas is improved. Therefore, the laser output is improved. In addition, since the temperature rise of the laser gas is reduced, the efficiency of power conversion into laser light is also improved. Therefore, the laser output is improved and the load on the laser gas cooling device is reduced, so that the device can be downsized.

[Brief description of the drawings]

FIGS. 1, 2, and 3 are a schematic diagram, an electrical equivalent circuit, and a voltage distribution diagram of an embodiment of the present invention, respectively. 4th
FIG. 5 and FIG. 5 are examples of a conventional axial gas laser. The same reference numerals in the drawings denote the same or corresponding components. DESCRIPTION OF SYMBOLS REPRESENTING Principal Parts of the Drawings 1... Axial gas laser 3... Laser tube 9... Inlet 11... Outlet 13. ₁ , R ₂ …… Resistance

Claims (1)

(57) [Claims] 1. A plurality of pin-shaped electrodes are provided at one end of a laser tube at equal intervals along the circumference, and a ring-shaped electrode is provided at the other end. A plurality of pin-shaped auxiliary electrodes are arranged at equal intervals, and two resistors connected in series are inserted between the auxiliary electrode and the pin-shaped electrode provided at the one end. An axial flow gas laser comprising an auxiliary electrode formed by connecting a power source for discharge between an intermediate connection point of the above and a ring-shaped electrode provided at the other end.